Dimethyl Sulfate → 3-(2,4-Dichlorophenyl)-5-difluoromethoxy-1-methyl-1H-pyrazole

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Reaction Steps

457.2 g of 3-(2,4-dichlorophenyl)-5-difluoromethoxy-1H-pyrazole from Example 3.2 were initially charged in 2300 ml of toluene. 227.3 g of dimethyl sulfate were added dropwise, and the mixture was heated at reflux for 3 h. After cooling, 500 ml of saturated aqueous NH4Cl solution were added, the mixture was stirred for 1 h and the organic phase was separated off and washed with water until neutral. Drying over Na2SO4 and concentration gave 377.8 g of 3-(2,4-dichlorophenyl)-5-difluoromethoxy-1-methyl-1H-pyrazole of a purity of 92.9% (GC). Yield: 73.1%. M.p.: 35° C.

Provenance & Evidence